Process of separating constituents of mineral oils



May 28, 1935. H. T.A BENNETT Patented May 28, 1935 i n UNITED vSTATES PATENT .OFFICE PROCESS F SEPABATING CONSTITUENTS 0F MINERAL OILS Harry T. Bennett, Tulsa, 0kla.,assinor to Mid-- Continent Petroleum Corporation, Tulsa, Okla., a corporation of Delaware Application June 23, 1933, Serial/No. 677,258

' 5 claims. (o1. 19e-'13) This invention relates to processes of sepa- With the foregoing and other objects in view, rating constituents of mineral oils, one of the the invention comprises the novel method, conobjects being to provide a method of recovering struction, combination and arrangements "of approximately all of the solvent from fractions parts hereinafter more specifically described of a mineral oil which have been separated by and shown in the accompanying drawing, which 5 treatment with a selective solvent. app1i' illustrates one form of the invention. However, cation is a'continuation in part of an applicait is to be understood that the invention come tion Serial No. 519,698,led by me on March 2, prehends changes, variations and modifications 1931. which come within the scope of the claims here- Mineral oils, including petroleum oils, and unto appended. 10 especially the petroleum lubricating oils, con- In the preferred form of the invention, BB

tain different constituents which may be sepadichlorethyl ether is employed as the selective rated'from each other by treating the oil with solvent, but other halogenated ethers may be a suitable selective solvent, and thereafter sepused, and some of the advantages of the present t arating the selected fraction from the other invention may be obtained in using various other fraction of the oil. solvents including nitrobenzene, phenol, aniline, s

Numerous advantages may be obtained by the cresol, furfural, dichlorethylene. trichlorethylene, use of such solvents to improve the quality of etc. the oil. The parainic. wax may be removed The drawing is a diagrammatical view of to improve the pour point of the oil, or the one form of an apparatus embodying y.the fea- 20 naphthenic portion may be separated from the tures of this invention. more valuable parainic portion to produce The oil to be treated may be confined in a a high viscosityv index lubricating oil which is container I and the solvent in a container 2.- non-sludging and has a low carbon content. 'Ihe oil and solvent may be transmitted through CII In the commercial treatment of these oils pipes 3 and 4 to a mixer 5 wherein the oil and 25 with a selective solvent, large quantities of rela'- solvent may be intimately mixed. The pipes tively expensive solvents are usually employed. 3 and 4 are provided with suitable valves to These solvents should be recovered from the regulate the delivery of 011 and solvent. The Oil fractions and reused fOr Subsequent eXtraC- solvent and oil, after being agitated in the mixer tions. Since the recovered solvent is used re-v 5, may be transmitted through pipe 6 to a sep-l 30 Peatedly. a Very Small 1088 0f SOIVGII during arator 1 where the oil is separated into fractions each treatment will eventually result in a conmore paramnie and more naphthenicthan the siderable loss of the solvent. Original 011,

In the preferred form of the invention, Aa very The more paran-mic fraction may be with large Percentage 0f the Solvent can be economi' drawn through pipe 8 to still 9 wherein a subcally covered fFQm the on fractions Wlth a' mm stantial portion of thesolvent is readily distilled imum decomposttmn of the solvent by dstimng from the oil preferably under a pressure less these fractlons at rela'twely 10W temperatures than atmospheric pressure. The solvent, which nd treating the same with steam' However is usually free of water 'at this time, is transa' .quantity of Solvent depending upon the ne" mitted through vapor line I0, condenser II and 40 ture of the Solvent is cgnta'ined in the con' pipes I2, -I3 and I4 to the solvent container 2. densed steam. The amount o f solvent contained valves I5 and 's being open and valve n being in the kcondensed steam is usually relatively closed I I lntm proportion to the volume of* water Aftera large portion of the Asolvent vhas been A, An object of this invention, therefore, is to separated from, the 011 m the vafuum stm 9 'd nomical and eflicientprocess and Steam may be Injected thlOllh pipe ZG to reprovl e an eco move the last portion of thensolvent from the oil.

apparatus for extracting mineral oil with a sol- 1 e effectivel The pipe 20 is prov1ded with a valve to control vent wherein the so vent may b y the delivery of steam to the still 9,. y

50 lo in removseparated from the steam emp yed At .this time, while steamvis injectedvmto the l nt from the oil fractions. mit huertshgybject iste provide a system wherestill 9, the valves I5 and I1 are open and valve vin a -highlyyeicient selectivev solvent be I closed so that the `solvent andcondensed reused for repeated extractions of oils with steam may fpass from the condenser II,: and practically no loss of'solvent. through pipes I2 and I8 to the separator or set- 55 tier 22. 'I'he solvent and water is thus diverted from the return pipe I4.

After the solvent has been removed from the more paraihnic fraction of the oil, this fraction is discharged through pipe 23 to a tank 24.

The more naphthenic fraction of the oil is transmitted through pipe 25 to a vacuum still 26 wherein the solvent may be separated from the oil in a manner similar to the separation which occurs in still 9. The readily removable portion of the solvent,- which is not subjected to the steam, may be transmitted through vapor line 29, condenser 29, pipes 30,v 3| and I4 to the solvent container 2, valve 32 being closed and valve 3i being open at this time. Thereafter, steam is introduced through a pipe 21 provided with a suitable regulating valve.

yWhen. steam is injected into the still 26, a valve 32 is opened and the valve 3 I closed, so that the solvent and condensed steam are transmitted y to the container 22.

The more naphthenic fraction of the oil in the still 26 maybe transmitted through pipe 34 to tank 36.

'Ihe free solvent which settles by gravity in the container 22, may be passed throughpipes 36 and I4 to the solvent tank 2. -The water containing dissolved or suspended solvent remaining in container 22 may be transmitted through a pipe 36 to a still 31. The solvent with about 10% to 20% of the water in the form of steam passes from the still 31, through vapor line 38, to a condenser 39, the condensate being transmitted through pipe 40 to a; separator 4I. The still 31 is provided with a pipe 42 for the discharge of the water remaining in the still after t the distilling Aoperation therein has been completed. V

The. solvent, which is Iseparated by gravity from the small quantity of water in separator 4I, is returned through a pipe 43, to the solvent container 2. The water in the separator 4I is discharged through a pipe 44, which preferably leads back to the. still 31, to 'provide for a removal of the solvent containedl in this water.

It will now be understood that almost all of the solvent may be transmitted in an endless course from the solvent container 2, through the separating station including the separator 1, the solvent recovery station including stills 9 and 26 for the separation of the solvent from the oil, then through return conductors leading back to said solvent container.

These return conductors include the 'return pipe I4 which receives the free solvent from the pipe I3 as well as solvent which is diverted through the. separating chamber 22. Said return conductors also include the pipe 43 which returns the smaller quantity of solvent obtained by distilling a portion of the water discharged from said separating chamber 22.

As an illustration of one form of this invention, I will n'ow describe a specific process where.-

in a chlorinated solvent, such as BB' dichlor yparts BB dichlorethyl ether in the mixer I ata temperature of about F. to 105 F. While at substantially the same ltemperature the mixture of oil and BB' dichlorethyl ether are trans-l mitted to the separator 1 where the naphtl'lenicl and paraillnic fractions gradually'separate from each other, the upper layer of material discharged through pipe 8 being more parai'ilnic than' the original oil, while the lower layer, discharged through pipe 25, is more naphthenic than the original oil.

The temperature in the vacuum stills 9 and 26 may be about 280 F., during the first part of the run, and it is desirable to thereafter increase this temperature to about 330 F., while introducing live steam throughpipes 20 and 21 to remove the last portion of the solvent.

During the rst part of the run in the stills 9 and 26 the recovered BB dichlorethyl ether may be transmitted directly to solvent containerI 2, and thereafter, when steam is introduced into the stills 9 and 26, the BB' dichlorethyl ether and condensed steam is preferably transmitted to the separator 22. ,The free BB dichlorethyl ether which settles in the separator 22, is returned to the solvent container 2 through pipes 36 and I4. The water remaining in the settler 22 may contain about 1% solvent, and this water is transmitted tothe still 31. About 10% to 20% of this water is distilled, with the result of removing practically all of the dichlorethyl ether, the resultant condensate being transmitted to the separator 4I, wherein substantially all of the condensed BB dichlorethyl ether may then be returned through pipe 43 to the solvent container 2. The water in separator 4I and still 42 may be discharged through pipes 44 and 42. However, the pipe 44 preferably leads from said separator 4I to the still 31. s

To simplify the illustration, I have shown a single separating chamber-1, but it is to be understood that the parafiinic fraction of -the oil may be subjected to successive mixing and separating operations, using additional quantities of fresh solvent; or the naphthenic solution resulting from one separating operation may be' used in preliminary mixing and separating operations, so as to remove some of the'naphthenic portions from the original oil before it is subjected to the treatment with fresh solvent.

In actual practice, I prefer to subject the fresh oil to a preliminary extraction, using the napthenic solution of another extracting operation to remove some of the naphthenic constituents of the original oil. Thereafter, the oil from which these naphthenic constituents have been removed, is mixed with fresh solvent and permitted to settle, so as to remove additional naphthenic constituents from the desired paraf- As a specic illustration of the results obtained from such operations, I will refer to the extraction of a mid-continent lubricatingoil, having a gravity of 26.4, a fiash point of 405 F., a viscosity of 255 at 100 F., and a.

vious extraction, and after separating into a.

layer more paramnic than the original oil and a layer more naphthenic than said original oil, the paraihnic layer was removed an'd mixed with fresh -BB' dichlorethyl ether, using 21,5 parts of the ether to 1 part of the oil. After being allowed to settle, the paraiiinic portion was removed and distilled to recover solvent therefrom.

The resultant parafilnic lubricating oil had a gravity of 30.8, a 'fiash point of 425 F., a viscosilt) of 198 at-100 F., and a viscosity index of "nie originaron was treated with smpnuric acid and clay before subjecting it tothe extracting process. The parailinic and naphthenic products may be subjected to alight treatment with sulphuric acid, using about V4 to 1/2 pound of the acid for each barrel of the oil, and thereafter contacted with a suitable adsorbent, `or absorbent material, such as fullers earth, or

`other suitable clay. When treated in this man'- ner, both products are valuable lubricating oils,

the greatest value being in the high viscosity index parafiinic oil,.having a highresistance to sludging and carbon formation, but the low viscosity index naphthenic oil is quite satisfactory for use in machines that do not require a high viscosity index lubricant. I

It is, of course, understood that suitable valves and pumpswill be employed to efficiently control the transmission of the several fluids from 'one station to another, and a complete commercial system which may be a countercurrent system will include numerous other details not shown in the accompanying drawing.

' However, this drawing is merely a diagrammatical illustration of 'one form of the invention, and in view of the foregoing disclosure, such details will be apparent to those skilled in the art. Furthermore, the invention extendsy to various modifications within the scope of the terms employed in the following claims.

I claim: l

1. The process of treating oils having different constituents which comprises mixing the oil -with a halogenated ether, separating the mixture into fractions, separately distilling one of steam to recover dichlorethyl ether from said' said fractions with steam to separate the halo- 'genated ether from said fraction, condensing fractions', condensingjsaid steam, and distillingsaid condensed steam to recover dichlorethyl ether contained therein. 4

3'. The' process of treating oils having high and low viscosity index constituents which comprises treating anv oil with dichlorethyl ether to effect a separation of the oil into fractions `having a higher viscosity index and a"lower viscosity index than the original oil, separately distilling said fractions and treating themwith steam to separate the dichlorethyl ether from said fractions, condensing said steam, distilling about 10 to 20 percent of said condensed steam to remove approximately all of the dichlorethyl ether contained in said condensed steam, and separating the last mentioned dichlorethyl ether from said condensed steam.

4. The process of treating oils having high and low viscosity index constituents which comprises treating an oil with dichlorethyl ether to effect a separation of the oil into fractions having a higher viscosity index and a lower viscosity in- .dex than the original oil, separately distilling said fractions under a vacuum, in theabsence of steam, to recover a large percentage of said dichlorethyl ethern from said fractions, Athereafter injecting steam into the liquid undergoing said vacuum distillation to continue the removal of dichlorethyl ether, condensing said steam, and distilling about 10 to 20 percent of the condensed steam to remove dichlorethyl ethertherefrom.

5. The process of treating lubricating oik 30 stocks having high and low viscosity index cnstituents which comprises adding b'eta' beta' dichlorethyl ether izo-the oil to be treated, agitating the resultant mixture of oil andv solvent at a temperature from about 80 to 110 F., allowing the mixture to settle into va fraction having a higher viscosity index than the original oil and a fraction YAhaving a lower viscosity index, separating said fractions, separately distilling said fractions under a vacuum to recover a large percentage of said dichlorethyl ether, and thereafter removing substantially all of the remaining dichlorethyl ether byintroducing-steam into the material undergoing said vacuum distillation, condensing said steam, removing the free dichlorethyl ether from the condensed steam, and

distillingl said condensed steam to'recover. sub-- stantially all of the dichlorethyl ether contained therein. 'r I l HARRY T. BENNETT. 

